Soldering: when to use torch vs iron [vs copper]?

Old 04-27-13, 09:05 PM
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Soldering: when to use torch vs iron [vs copper]?

I'd like to understand why different means of applying heat are used for various tasks. Specifically:
  • Electronics
  • Household copper plumbing
  • Gutters (galvanized or copper)
  • Roofing (flashing, repair)
  • Auto body filling

I have always used a soldering iron for electronic work, and a propane torch for plumbing. When considering using solder for auto body filler, I have found a torch is also recommended. I have recently, however, been looking at repairing some galvanized gutters and found a soldering copper ("soldering iron" with a copper tip) is recommended.

I can find plenty of explanations online about how to do each, but I have not yet found a good collection of the reasons for the tool used for each.

Old 04-28-13, 01:41 AM
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Normally you would use a soldering iron anywhere the flame would cause damage. You can also use a soldering iron for body work.
Old 04-28-13, 03:30 AM
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I guess it would take a pretty big iron for doing automotive lead work although I suspect you'd be hard put to find anyone that still uses it today
Old 04-30-13, 12:48 PM
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So, that suggests a torch could be used for gutter work (assuming there is no risk of fire) and that an iron could be used on plumbing?

Why is it that plumbing is almost always done with a torch (even though it it so often close to wood)? Why is it that it is so strongly suggested that an iron be used on gutters?

Old 04-30-13, 01:19 PM
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Plumbing is normally pretty thick compared to gutters or other sheet metal. Needs more heat. 30 yrs ago we had some giant soldering irons (1" wide tips) in my Navy electronics shops...they were used very very rarely early on for soldering lugs on to heavy cables where you didn't want to damage the insulation and open flames were a bad idea...and never in my later years. Mechanical connections took over. The metal work guys still had them...but I don't know what they were used for.

A propane/MAPP/acetylene torch can transfer a lot of heat for a quick solder joint...and no electrical supply required.

On gutters I'd guess that warping of the surrounding area would be a consideration as well.

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